Other Parts Discussed in Thread: TPS2490
Team,
Customer is evaluating LM5069 and try to qualify it in an existing design:
During our test, a short circuit or overload caused the device to switch back on. It is like the latch function is not working accordingly.
-Example overload:
When the overload limit is reached, the current is limited and switched off.
Afterwards it is switched on again for approx. 68ms. The pause time depends on the overcurrent.
-Example short circuit:
In case of short circuit, the current is limited for approx. 64ms and then switched off. After a pause
of approx. 1.1s it is switched on again.
Can you please explain what are the reasons for such behavior?
Here is the circuit used:
It was originally developed for TPS2490.
It is comparable to the typical application from the datasheet.
LM5069 VIN corresponds to the TPS2490 VCC
LM5069 SENSE corresponds to the TPS2490 SENSE
LM5069 GATE corresponds to the TPS2490 GATE
LM5069 OUT the TPS2490 OUT
LM5069 PGD the TPS2490 PG
LM5069 GND the TPS2490 GND
LM5069 TIMER the TPS2490 TIMER
The LM5069 PWR is connected with a 220k to GND.
We do not need a power limit in our circuit.
The LM5069 OVLO is connected to GND.
We do not need an overvoltage cutoff in our circuit.
The LM5069 UVLO is supplied with >3V at 24V.
In the experiment, the undervoltage cutoff is not tested.
After a short circuit or overload condition, the TPS2490 latches the circuit.
The circuit must first be reset via the EN, to operate again.
The LM5069, on the other hand, shows the behavior described above.
Can the LM5069 directly replace the TPS2490 in this use case?
What needs to be fine tuned to do so?
Thanks,
A.
